<!DOCTYPE HTML>

<html>
<head>
<title>WebGL 2.0 Test: BlitFramebuffer Result Must Be Displayed</title>
<style type="text/css">
.nomargin {
  margin: 0px auto;
}
</style>

<script>
function sendResult(status, detail) {
  console.log(detail);
  if (window.domAutomationController) {
    window.domAutomationController.send(status);
  } else {
    console.log(status);
  }
}

var gl;
var fbo;
var width;
var height;
var numFramesBeforeBlit = 15;
var numFramesBeforeEnd = 15;

function main() {
  var canvas = document.getElementById("c");
  gl = canvas.getContext('webgl2', {alpha: false, antialias: false,
                                    depth: false, stencil: false});
  if (!gl) {
    sendResult("FAILURE", "WebGL 2.0 context not supported");
    return;
  }
  width = gl.drawingBufferWidth;
  height = gl.drawingBufferHeight;
  fbo = gl.createFramebuffer();
  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
  var rb = gl.createRenderbuffer();
  gl.bindRenderbuffer(gl.RENDERBUFFER, rb);
  gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA8, width, height);
  gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, rb);
  var status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
  if (status != gl.FRAMEBUFFER_COMPLETE) {
    sendResult("FAILURE", "Framebuffer was incomplete: status = " + status);
    return;
  }
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);

  // Clear background of canvas to red
  gl.clearColor(1.0, 0.0, 0.0, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);

  // Repeatedly clear user framebuffer to green but only do blit the
  // last time, to ensure canvas was composited
  window.requestAnimationFrame(clearAndMaybeBlit);
}

function clearAndMaybeBlit()
{
  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
  // Clear user framebuffer to green
  gl.clearColor(0.0, 1.0, 0.0, 1.0);
  gl.clear(gl.COLOR_BUFFER_BIT);
  gl.bindFramebuffer(gl.FRAMEBUFFER, null);

  if (--numFramesBeforeBlit == 0) {
    gl.bindFramebuffer(gl.READ_FRAMEBUFFER, fbo);
    gl.blitFramebuffer(0, 0, width, height,
                       0, 0, width, height,
                       gl.COLOR_BUFFER_BIT, gl.NEAREST);
    gl.bindFramebuffer(gl.FRAMEBUFFER, null);
    // That's the only operation done to the canvas. Wait to signal
    // acknowledgment to the harness.
    window.requestAnimationFrame(waitForFinish);
  } else {
    // Do this again
    window.requestAnimationFrame(clearAndMaybeBlit);
  }
}

function waitForFinish()
{
  if (--numFramesBeforeEnd == 0) {
    sendResult("SUCCESS", "Test complete");
  } else {
    window.requestAnimationFrame(waitForFinish);
  }
}
</script>
</head>
<body onload="main()">
<canvas id="c" width="200" height="200" class="nomargin" style="position:absolute; top:0px; left:0px"></canvas>
</div>
</body>
</html>
